The present invention is generally directed to dispensing apparatus and more particularly directed to apparatus used in gravimetrically dispensing accurate predetermined amounts of dispersants, particulates, or a combination thereof.
Paint manufacturer is faced with the perennial problem of supplying to its customers many different colored paints and usually more colors than the manufacturer can, as a practical matter, keep in stock. The problem is especially acute in the supply of paint for vehicle refinishing, that is to say in the supply of paint for respraying vehicles, for example, a crash repair. The difficulty is that vehicle manufacturers supply their vehicles in many different colors and in subtly different shades. Even for a given make, model and color, slight variations can arise between the exact colors of particular cars due to variations in the batches of paint used in the manufacture. Also, colors fade with time due to exposure to UV radiation and new color recipes are needed to match the faded colors. Moreover, commercial transport operators often wish to respray their vehicles in their own distinctive color schemes. As a result, the number of paint colors in use is extensive and can run into tens of thousands.
Paint manufacturers succeed in providing the large number of colors called for by a method of blending. A number of basic or standard tints are produced that usually contain a single pigment but may contain a major proportion of one pigment and a minor amount of another sufficient to produce the standard color tint. A typical standard range will contain from 20 to 50 basic tints, which can be blended to give thousands of other colors. Thus, the refinisher or refinish paint supplier need only stock between 20 to 50 color tints depending upon the particular range of paints that it wishes to use.
In order to match color of the cars the refinisher repairs, the refinisher must mix these paints very carefully and very accurately against a recipe or a mixing scheme, which is supplied by the paint manufacturer. The recipe sets out the proportions of basic tints, which have to be mixed to match the exact color of the particular make, model and color variant of the repaired car.
The most conventional method is to manually weigh the components in accordance with a recipe and then mix them together to form a paint.
Automated devices have also been used. For example, dispensing devices are commonly employed in the art of paint mixing to dispense desired amounts of tints of certain color or characteristic to form paint. Typically, dispensing devices utilize a plurality of dispensing reservoirs with each reservoir having its own dispensing valve. Some of these dispensing devices are used to perform volumetric mixing; i.e. certain amounts of tints are individually dispensed by volume from their respective reservoirs. One of the major problems associated with conventional dispensing devices is the difficulty in dispensing accurate amounts of tints used to form the paint. This problem is further exacerbated when quantities of tints being dispensed are small, such as for example, in preparing refinish automotive applications.
Another problem associated with conventional dispensing devices is the phase separation of solids, such as pigments, present in the tint from a carrier medium, such as binder resin and solvent.
A number of ways have been used to dispense a plurality of components, such as dispersants or particulates in predetermined quantities, to form compositions, such as paints. U.S. Pat. No. 5,485,941 to Guyomard et al., attempts to address some of the foregoing problems by providing for pressurized containers and a loop through which flowable materials are recirculated to prevent phase separation. A pressurization fluid, such as nitrogen or air, is used to provide pressure to flowable materials. A buffer reservoir is used to transfer flowable materials under pressure. The reservoir then gravimetrically and volumetrically dispenses the flowable material through a dosing head under pressure in predetermined amounts. However, a need still exists for a simpler device that not only addresses the foregoing problems, but also ensures improved dispensing accuracy even in very small amounts of fractions of a gram.
The present invention is directed to a dispensing apparatus comprising:
(1) a plurality of recirculating systems wherein each said recirculating system comprises a reservoir containing a dispersant, a closed loop of a tubing connected to said reservoir, pumping means positioned in said loop for recirculating said dispersant to and from said reservoir at an elevated pressure, and a dispersant dispenser positioned in said loop;
(2) a frame assembly comprising:
(a) a dispenser actuator assembly for actuating said dispersant dispenser, said assembly positioned above a platform having a weighing scale positioned thereon;
(b) a movable table positioned between said dispenser actuator assembly and said weighing scale, said table having said dispersant dispensers of said plurality of recirculating systems positioned thereon;
(c) a pneumatic linear positioning system for moving said movable table in X and Y directions; and
(3) a controller comprising:
(a) means for retrieving a recipe for a composition from a database, said recipe comprising predetermined quantities of said dispersants, which when mixed together result in said composition;
(b) means for signaling said pneumatic linear positioning system to move, upon processing an address location signal from a processor, said table for engaging said actuator assembly with one of said dispersant dispensers selected in accordance with said recipe;
(c) means for actuating said dispenser actuator assembly to open or to shut, upon processing a nozzle control signal from said processor, a nozzle on said selected dispersant dispenser to gravimetrically dispense said dispersant into a container placed on said weighing scale; and
(d) means for generating a weight monitoring signal from said weighing scale to direct said processor to shut off said nozzle on said selected dispersant dispenser once an amount of said dispersant determined in accordance with said recipe is dispensed into said container.
The apparatus of the preset invention further comprises:
one or more particulates metering devices positioned on said moving table wherein said means for signaling, upon processing said address location signal from said processor, direct said pneumatic linear positioning system to move said table for engaging said actuator assembly with one of said metering devices selected in accordance with said recipe comprising predetermined quantities of one or more particulates; wherein, upon processing an auger control signal from said processor, said means for actuating dispenser actuator assembly initiate or terminate gravimetric release of particulates from said selected metering device into said container; and wherein said means for generating weight monitoring signal direct said processor to terminate the release of the particulates into said container once an amount of the particulates determined in accordance with said recipe is dispersed into said container.
The present invention is also directed to a method of producing a composition comprising:
(1) recirculating a plurality of dispersants thorough recirculating systems of an apparatus wherein each said recirculating system comprises a reservoir containing said dispersant, a closed loop of a tubing connected to said reservoir, pumping means positioned in said loop for recirculating said dispersant to and from said reservoir at an elevated pressure, and a dispersant dispenser positioned in said loop;
(2) retrieving a recipe for said composition from a database, said recipe comprising predetermined quantities of said dispersants, which when mixed together result in said composition;
(3) directing a pneumatic linear positioning system of a frame assembly of said apparatus to move in X and Y directions, upon processing an address location signal from a processor of said apparatus, a movable table to engage a dispenser actuator assembly with one of said dispersant dispensers selected in accordance with said recipe, wherein said table is positioned between said dispenser actuator assembly and a weighing scale of said frame assembly, said table having a plurality of said dispersant dispensers positioned thereon;
(4) actuating said dispenser actuator assembly to open or to shut, upon processing a nozzle control signal from said processor, a nozzle on said selected dispersant dispenser to gravimetrically dispense said dispersant into a container placed on said weighing scale; and
(5) generating a weight monitoring signal from said weighing scale to direct said processor to shut said nozzle on said selected dispersant dispenser once an amount of said dispersant determined in accordance with said recipe is dispensed into said container.
The forgoing method further comprising:
(1) directing, upon processing said address location signal from a processor, said pneumatic linear positioning system to move said table for engaging said actuator assembly with one of one or more particulates metering devices positioned on said moving table, said metering device selected in accordance with said recipe comprising predetermined quantities of one or more particulates; and
(2) actuating said dispenser actuator assembly to initiate or to terminate, upon processing an auger control signal from said processor, gravimetric release of particulates from said selected metering device into said container, wherein said means for generating said weight monitoring signal direct said processor to terminate the dispensing of said particulates into said container once an amount of said particulates determined in accordance with said recipe, is dispensed into said container.
An advantage of the present invention is to provide a smooth, steady (no pulsing) flow of the dispersant through the nozzle of the dispersant dispenser.
The present inventions advantageously provides for a 3-mode dispensing capability that provides a fast mode for dispensing the bulk of the dispersants or particulates and thereby reduce the cycle time, and slow and jog modes for increased dispensing accuracy.